Control system



Aug.- 28, 1923. 1 1,466,285 A. 1,. HARVEY CONTROL SYSTEM Filed Jan. 16 1920 vWnwwzssas: fylg; INVENTOR {J y Alba/fl. Hart 6y a u n I V ATTORNEY Patented Aug. 28, 1923.

(UNITED ,sTArEs PATENT OFFICE.

ALBERT L. HA VEY, or WILKINSBURG, PENNSYLVANIA, n'ssrenon r0 wEs'rING-- Hoosn ELEc'rnIca MANUFACTURING COMPANY, a CORPORATION or rENNsrL- Yum- ' common sys'rnm.

'Application filed January 16, 1920. Serial m5. 351,815.

T 0 alt whom it may concern:

Be it known that I, ALBERT L. HARVEY, a citizen of the United States, and aresident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Systems, of which the following is a specification. I

and particularly to such systems as are adapted to control the operation of electric motors in opposite directions andto establish dynamic-braking circuits therefor.

The object of my invention is to provide a system of control that shall be adapted to operate a motor in opposite directions and which shall embody a resistor that may suecessively function as a starting resistor and as a dynamic-braking resistor,

In 'control systems that have heretofore been employed, it has been customary to provide separatestarting resistors and dynamicbraking resistors and sufficient switching mechanisms to control the respective motoring and braking circuits.

In a control. system constructed in accordance with my invention, the directional switches function during motoring conditions to establish operating circuits for the motor, and they are also employed to establish dynamic-braking circuits for the motor when reverse direction of operation is desired or-when'it is desired toarrest the operation of the motor. A resistor, which is namic-braking resistor in a system which is capable of operatinga motorin forward and reverse dlrections.

a diagrammatic view of a control system embodying my invention, and Fig. 2 1s a diagrammatic view of a system of control.

embodying a modified form of my invention.

Referring particularly toFig. v1 of the drawing, directional switches 1 and 2 are provided for 'controllingthe direction of operation of a motor 3.which has a shunt electromagnet coil 8 which is energized when a push-button switch 9 is depressed Difield-magnet winding 4' and aseries field magnet winding .5. Directional switch 1 has contactors 6 and 7 that are actuated by an rectional switch 2 has contactors 10 and 11 and an actuating coil 12v which is energized of the motor.

by. a circuit that is completed when push-. button switch 13 is depressed. Push-button switches 9 and 13 are interlocked by, means of a pivotally mounted bar 14; which prevents the simultaneous operation of the two push-buttons and functions in such manner that, when one push-button is depressed, the 7 remaining push-button is raised. invention relates tocontrol systems A sectional resistor 15, having portions 16, 17, 18 and 19, andv an auxiliary resistor'hav-' ing portions 20 and 21, are connected in cirand are energized in accordance with the --a'rmature electromotive force, and coils 24:

and 25 that are also connected in series and are energized from a main supply circuit 28. Coils 24 and 26 are wound to assist each other and coils 25 and 27 are wound to oppose each other during forward operation Reversing the direction of operation of the motor reverses the polarity of coils 26 and 27, and, accordingly, they oppose and assist the coils 24 and 25, re-

spectively.

Arelay 29, having contactors 30 and 31 and a series actuating coil 32, is connec'ed to a point intermedlate resistor portions 20' Switches 22 and23 and 21 and a point intermediate portions 17' I and 18 of resistor 15. Resistor portions20 and 21 are of substantially equal resistance values and portions 17 and 18 areofsubstantially equal resistance values. Portions 16,-and 19 of resistor 15 are adjustable.

Assuming that the apparatus of the sys- 7 tem illustrated in Fig, 1 is positionedas Figure 1 of .the accompanying drawing is lished by depressing push-button 9 to energize electromagnet coil 8 from the supply circuit The switch 1 closes to establish a circuit from the positive side of supply circuit 28, through contactor 6, the armature of motor 3, contactor 11 of switch 2, portions 17 18 and 19 of resistor 15 and resistor portions 20 and 21 and field-magnet winding 5, to the negative side of the supply circuit 28. The series coil 32 of relay 29 is of relatively low resistance and constitutes substantially a shunt connection for resistor portions 18 1 and 21; The startin current which traverses portion 19 of the resistor .15 divides,

a portion. of the current traversing resistor 1.8 and the actuating coil 32 ot relay 29 and a second portion of the current traversing resistor portion 21. The relay 29 will. therefore, be actuated by the coil 32 to close contactors 30 and 31 and thereby establish enero'izing circuits for coils 2 1-, 25, 26 and 27 0t magnet contactors 22 and Switches 22 and 23 are so designed that the encrgization provided by coil 2% or coil 25, which is constant in polarity and degree, is not alone siti'llicient to close the correspond ing switch. It, however, the energization of coils 2 1- and 25 is supplemented by energization of coils 2t; and 27, to a degree corresponding to a predetermined motor speed, one oi the switches will actuated. The actuated switch being determined by the di rection of operation of the motor.

In view of the fact that the resistance of the armature of motor 3 is relatively small, the electromotive force that is applied to coils 26 and 27, when the motor initially connected to the supply circuit 28, is of a relatively small value. \Vith the increase of speed of the motor armature, the electromotive force applied to coils 2 6 and 27 increases correspondingly and, since coils 24 and 26 energize the core member of the switch 22 in the same direction, under the heretofore assumed conditions, switch 22 closes when a predetermined armature speed is reached and switch 28 is maintained open, since coils 25 and 27 magnetize the core member in opposite directions.

The closure of: magnet switch 22 shunts resistor section 21. and portions 18 and 15) oi resistor 15 from the motor circuit and establishes a direct operating circuit for the motor which includes contactoi '6, the motor armature, contactor ll, switch 2 and series field-magnet coil 5.

If, it is desired to arrest the operation of the motor, push-button 13 is depressed to such degree as to open the push-button switch 9 and thereby interru 'it the energiz- 'ing circuit of coil 8. The switch 1 opens to establish a dynamicdn'al;ing circuit for the motor 3 which extends from the motor armature, 'tln'ough cont-actor 11, resistor l5 and contact'or 7, to the motor arn'iaturc.

The shunt. field-magnet wind ing 4t is energized during motoring and braking operations from the supply circuit 28. Resistor portions 20 and 21. are connected .in shunt relation to portions 17 and 18 oi resistor 15, and, since the resistor portions 20 and 21v are of substantially the same resista'mfe value and portions 17 and. 18 are likewise of the same resistance value, the coil 32 of relay 29 is connected to points of the same potential and, therefore, it remains unenergized. then the relay 29 interrupts the energizing circuits for coils 24:, 25, 26 and 27, switches 22 and 23 will open.

it it is desired to reverse the direction of:

operation of motor 3, push-lmtton 13 is demapjuet winding 5, to the negative side oi the supply circuit.

The relay is actuated, when the motor is operated in the opposite direction, in siiibstantially the same manner as that described tor the forward direction ol operation oi? the motor. The coil 32 is of low resistance and isconnected in shunt with resistors 2t) and 1?. Relay 29 is, therefore, closed when a circuit for the reverse direction of operation of the motor 3 is established.

For the reverse direction of operation of the motor, the direction of the armature voltage is reversed and, therefore, the coils 25 and 27 of the switch 23 assist each other. This action tends to close switch where as, coils 24: and 26 tend to magnetize the corresponding core memberin opposing directions and therefore, the switch remains open. hen the motor speed increases suil'ioiently to effect the actuation of switch 23 by increasing the voltage applied to coil 27, switch 23 closes and shunts the active portions 16 and 17 ot resistor 15 and resistor 20 from the motor circuit.

()PQI'ZItlOIl ot the motor may be arrested by depressing puslrbntton 9 to such degree as to open push-button switch, 13 and "thereby interrupt the energizing circuit of coil 12. (,ontactors 7 and 1.1, when the corresponding switches are open, establish a dynamic-braking circuit which iruzludes resistor 15, to arrest the operation oi' the motor.

Fig. 2 illustrates a modified torm ot the invention shownv in Fig. 'l. A main line contactor 32-3 controlled by means of a coil ill which is connected in series relation to the coils S and 12 ot contactors l and 2. A sectional resistor 351, having adjustable portions Ill; and 37. constitutes a dynamicbraking resistor and a portion of the starting resistor. An auxiliary adjust-able resister 38 is provided in order that the reances respectively inserted in the motor circuit during starting and during dynamicbraking operations may be indcpclulcntly H r. ad ustable. lhe remaining apparatus of Fig. 2 is similar to that illustrated in Fig.

1 and since it performs the same functions,

it is similarly designated.

Forward operation of the system shown in Fig. 2 of the drawing is established by depressing puslrbutton 9 to complete a circuit comprising the coils S and 34 and thus admit the closing contactors fi and 33.

which includes resistor35.

The coil 3-1; of m aiii-line contactor 33is connected ins'eries-circuit relation with coilsS" and 12 and is energized when either coil 8 or coil 12 is energized.

The closure of contactor 6 establishes a circuit from thepositi ve side of the supply circuit28,through the armature ofmotor 3, contactor-11,-port on 36 of resistor -35, resistor 38, serles field-magnet winding "5 and contac'tor 33, to the negative side of the supply circuit; I r v t The operation ofthe motor is arrested by depressing push-button 13 toa degree sufiicient to interruptthe circuit established by push-button 9 and thus open contactors 6. and 33. Contaotor 33 interrupts the energizing circuits for coils 24 31161 25 to open switch 22; Contactors't' and 11 complete a braking circuit for the armature-of motor 3 To operate the systemin the reverse tion, push-button 13 is depressed to close contactors 33 and 10 by energizing coils 12 and34L 7 Since the direction of the voltage that is applied to the armature of motor. 3 is re-,

described, to establish'a circuit inshunt relation to the motor operatingcirciiit including: the resistors 37'and 38.

The system herein described and illustrated in the accompanying drawing employs a resistorwhich functionsas a start ing resistor and also as a dynamic-braking resistor. The switches 22 and 23 are differ entially wound in such manner that one of the switches is maintained open during motoringconnections and, therefore, a suitable value of resistance is maintained in the braking circuit during all operating conditions. If, for any reason,the switch that shunts the active portion of the. resistors fails to open, the motor is protected from an abnormal rush of current when braking connections are initially established by the portions of. the resistor that remain un-' shunted during motoring operations.

Although I have illustrated certain simple and preferred formsof my invention I desire that only such limitations shall be im-' posed as are'indic'ated by the spirit scope of the appended claims.

I claim as my invention:

1. A control system comprising a motor, a resistorand a plurality of contactors for starting said motor in forward and reverse directions of operation and adapted to emand ploy a portion of: said resistor-as a starting resistor and to establish dynamicbraking circuit for said motor including said resistor. r V

2. A controlsystem comprising a motor having an arn'iature, a divided resistor, and

a pair oi directional contactors for revers- 7 ing the. direction of operatio'n of said motor," sa d contactors being-adapted to connect. a,

portion-of. said resistor in'series withsaid armature for starting d motor and to coniiect all or said resistor n a dynamic-braking circuit with said armature for arresting theoperation of sa d motor. Y I

3. A control systcm comprising a resistor adaptedto function as a starting a motor,

resistor aiidas a braking resistor and relay means associated with fsaid resistor and adapted to be actuated'when motoring conditions prevail and to bade-energizeddurs ,ing dynamic-braking conditions, and means controlled byfsaid relay for shunting cer-- tain portions of said resistor.

control system, the combination, with a' dynamo-electric machine and aresistor; of means responsiveto the direction of operation of said machine for excluding diil er'entfportions of said resistor fromcir- ,cuit. l '2 H 5', Iii-a control system. the combination. with adynamoelectric machine and a resistor, of plural. means for excluding certain portions oif said resistor "from circuit, said means being respectively held open or closed in accordance with the direction. of

ope 'ation of said machine: I

6. In a controlsystem, the coii'ibinatioii with a supply circuit and a (lyiiamaelectric machine and a resistor oi? plural ii cans for excluding certain portions of said resistor from circuit. each 0'? said means havino; a

plurality of actuating coils respectively d machine energized from the armature oi? i and from said supply circuit. V s

7. In a control svstennthe coiiibination with a supply circuit and a dyna-iiio-elcctricniachine and a resistor oi plural means for excluding certain portions oi said rcsistoi, from circuit. each oi said ii'icans liav--v inn; a plurality oi actuatin coils rcspers tively energized from said supply circuit similarly and from the armature of said machine oppositely.

f 8. In a control systen'i. the conil'iination with a dynaii'io-elcctric machine and a resistor, of plural means for excluding certain portions of said resistor from circuit, each of said means being: subjected to a eiimulative or a differential effect dependent upon the direction of rotation of said machine.

9. In ,a' control system. the combination witha dynamo-electric machine and a res1stor,'of means forexcluding said resistor from. circuit, said means having a plurality ot actuating" coils havin a cumulative etitcct or a ditlnrmnial eit'ect dependent upon the direction oit rotation oi said machine.

10. In a control system. the combination. with. a supply circuit and a dynamo-elm; tric machine and a resistor, of means for excluding said resistor from circuit. said means having a plurality of actuating coils respiaftively energizml from said supply circuit always in the same direction and from the armature of said machine in opposite directions dependent upon the direction of rotation of said machine.

11. A. control. system comprising a dynaino-electric machine, a plurality of voltageahsorhin; devices one oi which is connected in partial shunt relation to the other, a relay connected between intermediate points .Tf said devices, means for employing a portion of said (iQJlCCS during motoring conditions of said machine and all of them during dynamic-braking conditions, and means governed by said relay for shunting said devices under motoringconditions only.

A control. system comprising a motor, a plurality of resistors one being connected across a portion of the other a relay con nectcd betweenintermediate points of said resistors, means for connecting a portion of said resistors to one side t said intermediate PfilTTiZS in circuit during motoring conditions and for connecting; the entire resistors in circuit during dynamic-braking con... ions, and means governed hy s d re- .121}; tor shunting s:- resistors, 'l\erel:)y no current traverses said relay during braking conditions.

14'. A control system comprising a motor, 7

a plurality oil resistors, one being connected across aportion of the other, a relay connccted between the mid-phints oli said resistor ineai s for coiniootin g; the one or the other half of said resistors in circuit dependent ugon the direction of rotation of said motor during motoring conditions and forconnecting the entire resistors in circuit during dynamic braking conditions to prevent current traversing said relay, and means governed by said relay for shunting the active half of said resistors under 1110- torine conditions.

In testimony whereof, I have hereunto subscribed my name this 5th day at January, 1920.

ALBERT L. HARVEY.

clay con- 

